Various forms of operational amplifiers have been designed for fabrication using conventional complementary MOS fabrication processes. For example, typical high and low output impedance operational amplifiers are shown and described in "A Two Chip PCM Voice CODEC with Filters" by Haque, Gregorian, Blasco, Mao and Nicholson, Jr. in the IEEE Journal of Solid-State Circuits, Volume SC-14, No. 6, December, 1979, pages 961-969. In general, such operational amplifiers provide an output signal which varies between a positive supply V.sub.DD and a negative supply V.sub.SS relative to an intermediate analog ground V.sub.AG in proportion to the difference in the voltage of two input signals. Many operational amplifiers have been designed for operation as Class A amplifiers. However, even when fabricated in CMOS, the high power dissipation of such circuits generally prohibits their use as output driver amplifiers in LSI circuits. To reduce power dissipation, operational amplifiers may be designed for Class B operation where both output devices are simultaneously off when the output signal is very near the analog ground. As a result, such operational amplifiers exhibit severe cross-over distortion, i.e. distortions in the output signal in the region of the analog ground. To simultaneously reduce power dissipation relative to the Class A case while minimizing the cross-over distortion, operational amplifiers may be designed for Class AB operation where both output devices are simultaneously on when the output signal is near the analog ground. Such circuits must be carefully designed to restrict the simultaneous operation of the output devices to the situation where the output signal is within a minimum threshold above or below the analog ground V.sub.AG. If not, the resulting reduction in cross-over distortion may be at the expense of excessive amounts of quiescent DC current.